This invention relates to trolleys and more particularly to a trolley assembly for hanging a sliding door. Typically, large sliding doors are hung from overhead tracks by means of trolleys that include a plurality of wheels that are received in the tracks of an overhead rail and are totally journaled in a structural body from which the door is suspended by a hanger attached to the body and to the door.
There are several different types of trolleys which are respectively adapted for use in different applications. For example one type of trolley permits the associated door to be swung about a horizontal axis which extends parallel to the overhead rail and through the trolley. Other types permit lateral movement of the associated door by rotation of hangers having offset intermediate portions. Still other types are designed for use with very heavy or with relatively light doors.
In order to reduce the manufacturing cost of these various hangers it would be desirable to provide a novel body which is strong and durable in construction and which is usable with a large number of different types of trolley hangers.
The doors which are suspended from these trolleys are normally relatively large and are often very heavy, exerting large forces on the bearings of the trolley wheels makes it desirable to provide bearings having high load capacities. Also, due to these high loads, and especially in the case of very large doors, it would be desirable to provide a bearing having reduced friction so that the effort required to slide the door is reduced.
Heretofore, it has been common to rotatably journal the axle of the trolley wheels in a bushing sleeve that is retained in the body of the trolley. This prior art structure provides a relatively great rotational friction and has a relatively high wear rate resulting in short life or generally early degradation of performance. It can be appreciated that it would be highly desirable to provide a trolley having a high load capacity in combination with a generally frictionless bearing assembly that has long life and is easy to assemble during manufacture. It would also be desirable if such a trolley included a body which was adapted to be used in other types of trolleys where a greater amount of friction could be tolerated.